Twisted neck, no other symptoms

Help! One of my Ameraucana hens came out of the coop yesterday with her neck all twisted up. I'm seeing no other symptoms. No discharge, eating drinking and pooping okay. She is separated from all the other birds. I got some Vitamin B liquid yesterday and have been giving her that. I don't want to cull her if this is just a vitamin deficiency, but I also don't want to not cull her if it's something that can't be treated or may be something that can spread. She is 20 weeks old and has been fed Countryside Organics layer feed.

Thank you for any advice. I am pretty new to chickens and doing my best to find my way.